What is Ricin?

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(Memphis) Ricin, the poison detected in letters mailed to at least two politicians this week, is a toxic protein derived from the castor oil plant.

Dr. Abby Parrill, the chair of the chemistry department at the University of Memphis, explained, "The beans make it. You just have to purify it."

Castor oil is usually extracted from the plant. What's left usually contains about 3 - 5 percent Ricin, according to Parrill.

The toxicity of Ricin depends on how it's exposed.

Parrill said breathing it in would be 1,000 times more toxic than ingesting it.

When inhaling the substance, less than 2 mg may be enough to kill an adult of average weight.

Parrill said that if one comes into contact with Ricin, "Wash thoroughly, get rid of the clothes you were wearing, mostly to make sure you don’t ingest it accidentally or get it enough in the air."

There is currently no FDA-approved antidote.

Ricin prevents the body from creating proteins.

If inhaled, "it hits the lungs first, and as you shut down protein synthesis in all the cells around the lungs, the lungs can fill with fluid, coughing," Parrill said.

Some exposed can also experience severe diarrhea, nausea, seizures and shock. Those who survive may suffer from long-term organ damage.

The toxicity is the reason castor oil plants are not commonly sold.

Judy Westpy, who sells plants at Country Gardens Nursery, said, "The only way I’ve ever seen them is if somebody is growing the plant, they collect the seed and pass them along. I’ve never seen the seed for sale."

Westpy said customers rarely ask for it. Those who do are interested in it for landscaping.